Hydraulic jack



June 23, 1931. A. HOPKlNS HYDRAULIC JACK 2 Sheets-Sheet 1 Filed Jan. 6, 1928 A TTORNEYS A. c. HOPKINS 1,811,085

HYDRAULIC JACK June 23, 1931.

Filed Jan. 6, 192B 2 Sheets-Sheet 2 'IINVENTOR /7r//7ur (1 1/0 Patented June 23, 1931 UNITED STATES PATENT OFFICE:

ARTHUR C. HOPKINS, OF NILES, MICHIGAN, ASSIGNOR TO NATIONAL-STANDARD COM- PANY, OIE NILES, MICHIGAN HYDRAULIC JACK Application filed January 6, 1928. Serial No. 244,840.

The main objects of this invention are: p First, to provide an improved lifting jack of the hydraulic type whichis very powerful and easily operated and controlled.

Second, to provide an improved hydraulic lifting jack in which the fluid is effectively retained.

Third, to provide an'improved hydraulic lifting jack in which the operating parts are compactly arranged and not likely to get out of repair. 4

Fourth, to provide a lifting jack of the hydraulic type having a substantial throw which is very compact when retracted.

Objects pertaining to details and economies of my invention will definitely appear from the description to follow. The invention is defined in the claims. p

A structure embodying the features of my invention is clearly illustrated in the accompanying drawings in which:

Fig. 1 is a plan view of my improved lifting jack, the actuating lever being partially broken away.

Fig. 2 is a .fragmentary side elevation, the lifting lever being shown in an :elevated'position by dotted lines and in retracted position by full lines.

Fig. 3 is a detail view mainly in vertical longitudinal .section on line 33 of Figs;

1, 4'and 5.

Fig. 4 is a detail view mainly in transverse vertical section on a line corresponding to line 4-4 of Figs. 1, 3 and 7.

Fig. 5 is a detail fragmentary view mainly in section on line 5-5 of Fig. 3 showingthe arrangement of the valves and passages.

Fig. 6 is a fragmentary section on line 6-6 of Figs. 4 and 5. j

Fig. 7 is a detail section on line 77 of Figs. 1 and 4 showing details of the operating connection for the actuating lever to the pump.

Fig. 8 is a detail section showing details of the exhaust valve releasing means.

Referring to the drawings, the frame of my improved lifting jack in the embodiment illustrated comprises a pair of side members 1, Iconnected in spaced relation by cross members 2, 3 and 4. The frame is provided with a pair of front carrying wheels 5 and rear caster wheels 6, these caster wheels being supported on brackets 7.

A lifting lever 8 is pivotally mounted on the cross member with the head 9 pivoted at 10 on the outer end of the liftingv lever. Links 11 are pivoted to the frame at 12 and to the head at 13 thereby maintaining the head in an upright position during the swing of the lifting lever. A spring 14 is connected at 15 to the frame and at 16 to the head, the spring acting to return or collapse the lift-ing lever and the parts connected thereto.

At the rear end of the frame I mount a cylinder block 17 which is provided with journals 18 whereby the cylinder .block is pivotally or tiltingly supported on the frame.

The cylinder block is provided with a pump cylinder 19 with which the-plunger 20 coacts. The cylinder is provided with a packing gland designated generally by the numeral 21 The cylinder block also constitutes a head member for the ram cylinder 22 which is threaded into the cylinder block and disposed horizontally between the side members of the frame. The ram 23 projects from the ram cylinder and. is pivotally connected to the lifting lever 8 at 24.

The ram cylinder is providedwith a pack ing designated by the numeral 25 and is surrounded by a cylindrical casing 26 coacting with the cylinder. and its head to provide an annular sump 27 surrounding the cylinder 22. Adjacent its packing the cylinder 22 is provided with an. annular fluid collecting groove 28 and with a drain or passage 29 opening to the sump, preferably at the top of the cylinder. It should be above the liquid level.

The lower end of the pump cylinder is connected to the sump by the passage 30 controlled by the check valve 31, this being the inlet valve of the pump. The valve 31 illustrated is aball valve held on its seat by the spring 32. i

The pump cylinder is connected to the ram 1 cylinder by a port 33, this being the discharge port of the pump which is controlled which is provided with a handle 41 at its outer end. This lever is forked at its inner end and its arms 42 are pivoted on the journals 18 of the cylinder block.

The actuating lever is connected by the links 44 to the cross head 45 on the plunger 20 so that when the lever is oscillatedthe fluid is pumped from the sump jinto thehead end of the ram cylinder, forcing, theram plunger outwardly, thereby actuating the lifting lever 8. 1

To permit the return of the lifting lever I provide means for opening the return or exhaust valve 37 which, in the embodiment illustrated, consists of the plunger rod 46, see Fig. 6. This plunger rod is provided with a suitable packing 47. The outer end of the plunger rod is connected to one arm of the bell crank lever 48 which is pivoted at 49 on a bracket 50 secured to the frame, the connection being to a pin 51 on the plunger rod engaging a slot 52 on the bell crank lever 48. A rack 53 is reciprocatingly mounted on i the upwardly projecting arm 54 on the bracket 50. The rack is slotted at 5 5 to engage the pins 56 projecting from the bracket. 1 I

The rack. is connected to the lever 48 by means of a pin 57 on the rackengaging a slot 58 in the lever 48 so that when the rack is forced upwardly the valve 37 is held from its seat, allowing the fluid to return to the sump under the action of the load and of the spring 14. The spring returns the ram when there is no load upon the lifting lever.

The rack is held normally upward by means of the coiled spring 59. To actuate the rack the lever 40 carries a pawl 60 which is mounted in a slide 61 and controlled by the rod 62 having a handpiece 63 adjacent the handle 41 so that by a pull on this handpiece 63 the pawl is engaged, thereby permitting the opening of the valve through a manipulation of the lever 40. The amount of the opening can be accurately gaged thereby timing the return movement of the lifting lever.

A spring indicated at 64 returns the pawl to disengaged position. The'sump is sealed or closed to atmospheric ressure .so that when the fluid is drawn rom the sump a artial vacuum is created in the sump chamtier, resulting in drawing any fluid t at may pass along the plunger back into the sump, that is, it escapes into the sump through the drain 29 rather than being forced through the packing.

# cylinder below its packing to the sump and A drain connection 65 leads from the pump the art to embody opens to the sump above the liquid level thereof.

My improved lifting jack is easily operated and at the same time powerful and the return thereof is readily controlled. The structure is compact and at the same time strong and durable.

A further advantage of the construction is that by engagement of the releasing pawl with the rack, the actuating lever may be connected in any desired position to serve as a handle for manipulating the jack. For instance, if it is desired to lift the jack upon a curb, the actuating lever may be swung to an'elevated position and the pawl engaged with the'rack. The front end of the jack may ,then be raised by ado'wnward pressure on the actuating lever to elevate the front wheels above the curb. The actuating lever may then be swung to a lower position and engaged with the rack to elevate the rear' embodiment which I have found highly satisfactory. I have not attempted to illustrate certain modifications and adaptations which I contemplate as it is believed that these disclosures will enable those skilled in or adapt my improvements as may be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a lifting jack, the combination of a frame, a lifting l'ever pivotally mounted on said frame, a cylinder block j ournaled 'on said frame for tilting movement and provided with a pump cylinder, a pump plunger, a ram cylinder carried by said cylinder block, a

ram pivotally connected to said lifting lever,

a sump, a. valved intake from said sump to said pump cylinder, a valved discharge port from said pump cylinder to said ram cylinder, a valved exhaust connection from said ram cylinder to said pump, an actuating 1ever pivoted on the journals of said cylinder block, links connecting said actuatin lever to sald plunger, a releasing means or the exhaust valve comprising a push rod, a pivoted releasing lever operatively connected to said push rod, a segmental rack mounted for reciprocating movement in a plane parallel to the plane of oscillation of said actuating lever and operatively connected to said releasing lever, a return spring for said rack, and a tripping pawl on said actuating lever adapted to be selectively engaged with the teeth of said rack.

said frame, a cylinder block journaled on said frame for tilting movement and provided with a pump cylinder, a pump plunger, a ram cylinder carried by said cylinder block, a ram pivotally connected to said lifting lever, 11.

sump, a valved intake from said sump to said pump cylinder, a valved discharge port from said pump cylinder into said ram cylinder, a valved exhaust connection from said ram cylinder to said sump, an actuating lever pivoted on the journals of said cylinder block. links connecting said actuating lever to said plunger, and means for opening said valved exhaust connection operatively associated with said actuating lever to be operated thereby with the actuating lever in different positions.

3. In a lifting jack, the combination of a frame, a lifting lever pivotally mounted on said frame, a cylinder block mounted on said frame for tilting movement and provided with a pump cylinder, a pump plunger, a ram cylinder carried by said cylinder block, a coacting ram pivotally connected to said lifting lever, a sump, an intake valve for said pump connected to said sump, a discharge valve for said pump cylinder delivering to said ram cylinder, an exhaust valve controlling the return of the fluid from said ram cylinder to said pump. an actuating lever operatively connected to said pump plunger, a releasing means for the exhaust valve comprising a segmental rack mounted for reciprocating movement in a plane parallel to the plane of oscillation of said actuating lever and operatively connected to said exhaust valve, and a tripping pawl on said actuating lever adapted to be selectively engaged with the teeth of said rack.

4. In a lifting jack, the combination of a frame, a lifting member, a cylinder block mounted for tilting movement on said frame and provided with a pump cylinder, a coacting pump plunger, a ram cylinder carried by said cylinder block, a ram coacting with said cylinder and operatively connected to said cylinder and operatively connected to said lifting member, a sump, a discharge valve for said pump delivering to said ram cylinder, an intake valve for said pump cylinder connected to said sump, an exhaust valve for said ram cylinder delivering to said sump,

. an actuating lever pivot-ed 011 the journals of said cylinder block, a link connecting said actuatinglever to said plunger, and a releasing means for said exhaust valve including said actuating lever.

6. In a lifting jack, the combination of a frame, an actuated member carried thereby, a pump mounted on said frame, a ram cylinder operatively connected to said pump, a coacting ram operatively connected to said actuated member, a sump, said pump being operatively connected to said sump and said ram cylindor'having an exhaust valve connection to said sump, a pivoted actuating lever for said pump, means for controlling the said exhaust valve including a rack, and a. coacting tripping pawl carried by said lever whereby said exhaust valve may be actuated with the lever in a number of positions.

- In witness whereof I have hereunto set my hand.

ARTHUR C. HOPKINS.

said lifting member, a sump,a discharge valve for said pump delivering to said ram cylinder, an intake valve for said pump cylinder connected to said sump, an exhaust valve for said ram cylinder delivering to said sump, an actuating lever pivoted onthe ournals of said cylinder block, a link connecting said actuating lever to said plunger, a releasing means for said exhaust valve comprising a push rod, a pivoted releasing lever, one arm of which isconnected to said push rod, a segmental rack mounted for reciprocating movement in a plane parallel to the plane of oscillation of said actuating lever and connected to the other arm of said releasing lever, a return spring for said rack, and a tripping pawl on saidactuating lever adapted to be selectively engaged with the teeth of said rack. I

5. In a lifting jack, the combination of a frame, a lifting member, a cylinder block mounted for tilting movement .on saidframe and provided witha pump cylinder, a coacting pump by said cylinder block, aram coactlng With lunger, a ram cylinder carried 

